Hi all, I know you've read hundreds of threads with people having hesitation and choking problem. But here is something new for me, I've had this problem one Sunday after I filled from a SHELL gas station. (I'm not dissing Shell as a whole, just that one station probably had bad gas, atleast thats what i thought) So I went on searching and reading on my fav forum YotaTech and google ofcourse, and started to troubleshoot. This is what I did so far:

1. Checked my (recently installed) spark plugs. Good
2. Checked my OEM wires, good voltage and no obvious leakage. Good
3. Tried some famous fuel injectors (worked for couple of days only). Not Good
4. Cleaned up air intake and throttle body. Good

after all this, no results. So today I dug a bit deeper to check the resistance on all the injectors. I knew its a fairly lengthy project, so i took my time and also took pictures as i went.

Diagnosis:
1. All injectors have good resistance.
(15.4 - 15.8 on passenger side & 14.3-14.8 on driver's side) Good.
2. All injector wires have good voltage.
(11.58 on almost all of them)
3. Cleaned the manifold bigtime. (it had 12 years of gunk init)

Issue:
Now that I have done some much work to pull it all apart this far, I don't want to put it back in the same condition.

What should i do?
- Should I interchange the suspected cylinder 2 injector with another one to see it still misfires?
- Should I take the injectors out and clean them? (how? which cleaner?)
- I would like to prevent the compression test. (too much work, i guess )

HEEELLLPPP...........
This is what my engine looks like now. My handicapped runner :S

 

How did you get from this:

to this:

What makes you think #2 is bad?

 

I'm sorry... I forgot to mention. 2-3 times a month i get P0302.

 

you bought the wrong spark plugs. make sure you use stock spec plugs.

 

I have OEM (Denso's), bought from Toyota Dealership

 

try swapping the coil packs to see if the miss moves.

 

I already tried that. I swapped all three coils periodically, but same error.

 

If you're sure the plugs are good I would say it's pointing to an injector. Your readings though indicate they are good... Unless they are electrically functioning but the tips are clogged. IDK.. anyone else have any ideas?? I would guess since you have it torn down that far you might as well replace and or clean/test the injectors.

 

Thnx kball. Yea, thats what i am also thinking. But i wanted to know if someone else did something like this before and maybe have a suggestion for me.

I don't want to buy a $120 injector just coz i suspect it's bad. I know the rings only cost ~$12 at the dealer and ~$4 at AutoZone/O'Rielly, so i wanted to start from that.

Any ideas/suggestions ?

 

There's many threads about this issue, search to read through them as they have some good info.

And you might not need to buy a new injector. Check out http://www.witchhunter.com/

 

I did read a lot of them, but most of the people fixed the problem by replacing the Injector. Which does not seem to be the case.

So i'm going to get the compression tester tomorrow from Autozone and try that. Will update you guys with pix n results.

Thnx.

 

good lucy with the compression test. Sounds like a possible valve issue which is expensive, Trust me.

 

Hopefully not My brother says it might be the Piston ring :S

 

I've heard of people taking their injectors out and (i'm pretty sure, but don't hold me to it) running a 9volt battery across it and looking at the spray pattern to see how it looks. Might be worth looking into... I've heard the people who ship there injectors in to get tested and cleaned always are happy with the results. not sure on that witchhunter place specifically but it sounds like they know what there doing with 2 ultrasonic baths and multiple stages

 

I would bet money thats in your top end, its unlikely that a piston ring would all of a sudden fail bad enough to create compression loss significant enough to cause a misfire.

Have you had this truck a while? Do you know if the valves have ever been adjusted or checked for proper clearance? Valve adjustments at the specified intervals are crucial to avoid cracking in the casting between the valves in the heads.

I'm open to new problems and solutions, but I think this is gonna come down to an injector, or valve/cylinder head issue.

As for witchhunter.com, they have an outstanding reputation. If you have over 100k on that 3.4, it wouldn't hurt to have your injectors cleaned and tested.

 

yea - i sent my injectors to witchhunter a few weeks back - great place/service to get em cleaned. I had 150k on mine, so i figured why not while they were already out. Worth it imo before you start tearing the block apart.

 

If you swap the #2 injector, swap it with one from the other side of the engine so if it is that, at least the bad injector will now be on the side that's NOT under the intake plenum and be a lot easier to get to next time.

 

Thats a good idea

But I will consider sending the injectors. I just don't have $120 ($20x6) to spend at the moment.

 

Hi all, after going through the pain of opening the injectors and cleaning all of
them, and replacing the O-rings (all 12 of them). This is what I found:

Cylinder #2 (the cylinder in question) DID have a CLOGGED injector. That made me very happy that, that's all it was. But after putting all this together, it is still doing the same but haven't thrown a code yet...

Now, once I get the code, I will perform the compression test...

:'( I'm very close to giving up and sell this runner ...

 

how did you unclogg it? i think nows the time to send them out for a professional cleaning. just send that 1 out if your broke